Photo-electric tube



May L M PRESSLEIQif A PHOTO-ELECTRIC TUBE Filed April 18,'1951 NVENTR. By I max Prssler' HTToRIEY Patented May 1,

PATENT OFFICE.

PHOTO-ELECTRIC TUBE Max Pressler, Leipzig,

Germany, assignor of fifty percent to Radio Patents Corporation, New York, N. Y., a corporation of New York Application April 18, 1931, Serial No. 531,099

. In Germany April 26, 1930 v3 Claims.

This invention relates'to a new photoelectric tube and method for manufacturing the same, and more particularly to tubes of the vacuum or gaseous type.

5. This type of photoelectric tube, as is well known, generally consists of a vessel, preferably of glass either completely evacuated or led with a gas of proper nature and pressure, and including a cathode electrode with a light sensitive surface and an anode electrode to cooperate therewith.

According to the usual method of manufacturing tubes of this type, the photoelectric substance, such as potassium, caesium, etc., is

' brought into the tube and evaporated by the application of heat from the outside. Afterwards the tube is allowed to cool down whereupon the photoelectric material produces a deposit on the wall of the vessel.

One of the main diiculties of this process consists in the limitation of the deposit or precipitation of the photoelectric material to definite portions within the tube, as it is necessary to leave the remaining parts free to allow ready passage to the operating control light rays.

It has already been proposed in the co-pending patent application Serial No. 324,107, led December 6, 1928, to provide a hollow body within the tube or vessel which maybe filled from the outside during the manufacturing process with a cold liquid, so that duringthe heating period of the tube, the deposit will be limited to that part of the tube being cooled during the.

process.

The present invention is a further improvement of this process and has for its object to provide means for depositing a photoelectric surface of any desired conguration to be used for any specific purpose.

A more specific object of the invention is a photoelectrlc tube structure in which the photoelectric material is deposited on the outside Wall of a hollow body, preferably of tubular form which forms "part of an inside wall of the tube and which may have any desired shape and is readily accessible at both of its ends for passing a'cooling medium during the depositing operation.

A more specific object of the invention is to provide means whereby the photoelectric deposit may have the shape of a grating with light-sensitive strips arranged at denite distances from each other.

These and further objects of the invention will become more apparent from the following ythe depositingv operation.

(Cl. Z-27.5)

description taken with reference to the accomv panying drawing, which illustrates, by way of example, practical embodiments of the invention. The description, however, shouldl be regarded as being illustrative only of the broader 00 principle and scope of the invention, as might be obvious, and as set forth in the appended claims. y

Figure l illustrates a photoelectric tube of simpe construction embodying the principle of the invention.

Figure 2a is a structure similar to Figure 1, in which the photoelectric surface has the form of parallel strips at denite distance from each other.

Figure 2b illustrates schematically a shutter to be used in connection with the tube structure of Figure 2a.

Figure 3 shows another way of accomplishing the object according to Figure 2a. 75

Figure 4 is a schematic showing of the .photo tube and shutter in a light system.

Similar reference characters denote Vsimilar parts throughout the diierent views of the drawing.

The invention contemplates broadly a structure in which one or more hollow bodies, preferably in the form of thin tubes, are arranged Within the tube itself, whereby their outside wall forms a part of the inside wall of the tubes in such a manner that there are at least two openings leading to the outside so as to allow the passage of a cooling medium such as a liquid or gas, during In this way the precipitation of the light-sensitive material is con- 59 fined to the outside surface of the hollow body within the tube. This latter may be given any shape or configuration for obtaining any specific object, as will be described in more detail. I

Furthermore, this new expedient-according to -1'1 thc invention makes it possible to use comparativelcy thin members which may be bent in any desired way to assume a desired figure or shape and covered with the light-sensitive material. In this respect, the invention presents a meritorious and important advance of the art, in that it makes it possible to adapt the photoelectric tube orl rather the shape or configuration of the lightsensitive deposit to various optical problems of specific nature.

Referring to Figure 1, this illustrates a simple photoelectric tube in cross-section, embodying the invention. The tube body is shown at 1 and constitutes a torus or body of revolution, which is obtained by rotating the boundary surface designated by 9 around a central axis x--r, in such a manner that a central tubular body 2 is obtained with outside openings 3 and 4 through which, during the depositing process, a cooling medium, such as liquid or gas, may be passed.

In this manner, the precipitation of the photoelectric substance is confined to the outer surface of the body 2 as illustrated at 5. Cooperating with the pliotoelectric cathode 5, there is a spirally wound anode wire 6 connected to outside terminal posts 7. The spiral shape of the anode 6 allows a ready passage of the incident light rays impinging upon the photoelectric surface 5. The photoelectric surface may be connected to an outside terminal post in any. well known manner.

Referring `to Figure 2a, this shows a structure similar to Figure 1, with the difference that the body 2 has been extended and arranged in a winding shape with parallel portions at definite distances from each other, so that in connection with a rectangular shaped net-like anode 10, the practical equivalent of a light-sensitive surface consisting of light-sensitive parallel strips, is obtained. This structure is useful in connection with many problems; for instance, as shown in Figure 2b, which diagrammatically illustrates a control shutter for intercepting the beam of light acting upon the tube. This type of shutter 11, as shown in Figures 2b and 4, is provided with parallel openings or slits 12 of definite length and distance corresponding to the photoelectric surface strips of the tube according to Figure 2a. During the open position of the shutter, as is readily understood, the slits 12 are in a position to register with the parallel portions of the tube 2 or the photoelectric surface strips in such a manner that with comparatively slight movement of the shutter in either direction indicated by the arrows, the entire resultant light-sensitive surface is darkened by the solid parts of the shutter.

In other words, by using this type of photoelectric tube and cooperating shutter, it is possible to release a maximum of photoelectric current with a minimum of mechanical movement. Figure 4 illustrates a top view of a photoelectric tube and shutter combination of this type corresponding otherwise to Figures 2a and 2b. A source of light 13 and lens 14 are shown in the usual manner.

A further application of a tube of the type according to Figure 2a which, in other words, is a kind of a light-sensitive grating, consists in its use in connection with a spectrometer arrangement either of the prism spectrometer or grating spectrometer type. As is well known, the spectrums produced by such devices Acontain certain pronounced bright lines parallel to each other at a definite distanceand being characteristic of the nature of the chemical substance under investigation.

By placing the parallel portions of the body 2 according to Figure 2a at distances corresponding to the distance of the characteristic lines of a cer-l tain spectrum, this type of photoelectric tube may be readily used for indicating or controlling' purposes. It may serve, for instance, as an indicating or control device in metallurgical processes to ascertain that a certain stage in the process is reached, this stage being characterized by the ing a discharge current in the tube in the knownA manner which can be used for producing a required control or indication. I

Figure 3 shows a further tube structure for `accomplishing a similar object to Figure 2a in a somewhat different manner. In this tube, a plurality of thin hollow bodies 2, 2, 2', as shown in the example, are arranged instead of a single body 2, as per Figure 1, so as to present a number of passages for the cooling medium. The tubes may again be arranged parallel to each other, so that the effect obtained will be equivalent to Figure 2a, as is readily understood.

What I claim is:

1. A photoelectric tube comprising a vessel of insulating material; a tube of insulating material therein having wound parallel portions at definite distances from each other, said tube being integral with said vessel and having its outs ide surface constitute a part of the inside surface of said vessel; an anode, and a light sensitive dej posit on the outside of said glass tube.

2. A photoelectric tube comprising a glass vessel; a glass tube therein having wound parallel portions at definite distances from each other, said glass tube being integral with said vessel and having its ends open to the outside of said vessel for passing a cooling medium therethrough and having its outside surface constitute a part of the inside surface of said vessel; a netlike anode in front and parallel to said wound glass tube and a light sensitive deposit on the outside of said glass tube.

3. A photoelectric tube comprising a vessel of insulating material; a tube of insulating material having wound portions of a predetermined configuration, said tube being mounted within said vessel and having its outer surface constitute a part of the inner surface of said vessel; an anode within said vessel; and a light sensitive deposit on the outer surface of said tube.

MAX PRESSLER. 

